Abstract: A high-sulfur copper mine in Jiangxi gradually shift to underground mining，as the ore properties has changed greatly, on-site process is difficult to adapt to the changes in the nature of selected ore, resulting in decreased copper recovery rate.In view of this situation, with the overall pattern of process remains relatively stable, then study on the application of new efficient collecting agent PLQ-4, also optimize and transform middlings regrinding reselecting system.The results show that using PLQ-4 substitute parts of butyl xanthate, add more middlings directly to the regrinding system, reduce the unsolved eventually get away from the unnecessary cycle of copper minerals in the process，eventually obtain a copper concentrate grade of 22.75%, copper recovery rate of 83.85% ,Compared with the laboratory parameters in the simulation under technology conditions of the site, with equal copper concentrate grade, the copper recovery rate improved by 2.82.

Key words: High-sulfur copper ore, Regrinding of middlings, PLQ-4, Cu recovery